Getting a rocket ride to the red planet is the easy part. It's touching down on Mars that aerospace engineers consider to be one of the greatest challenges in the solar system; in fact, about a third of missions successfully launched to the red planet don't survive a landing.

"It takes thousands of steps to go from the top of the atmosphere to the surface, and each one of them has to work perfectly," Rob Manning, the chief engineer at NASA's Jet Propulsion Laboratory, said in a video.

The 789-pound lander will officially begin its descent to Mars at 2:40 p.m. ET on Monday and touch down by 2:54 p.m. After that, NASA hopes to use InSight to decode the internal structure of Mars, among other mysteries.

Here's a minute-by-minute look at the biggest moments of InSight's landing sequence — any of which could doom the robot.

This story has been updated. It was originally published on November 23, 2018.

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2:40 p.m. ET: The InSight lander, tucked inside an entry capsule, separates from the spacecraft that carried the mission to Mars.

An illustration of NASA's InSight probe attempting to land on Mars.NASA/JPL-Caltech

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2:41 p.m. ET: The entry capsule turns to orient itself for atmospheric entry at just the right angle — about 12 degrees relative to the surface.